Till now, ISRO had to depend on foreign launchers for communication satellites weighing more than 2,300 kg. The GSLV MkIII-D1 is capable of lifting payloads of up to 4,000 kg into the Geosynchronous Transfer Orbit (GTO) and 10,000 kg into the Low Earth Orbit.

In tomorrow’s mission, the vehicle is scheduled to launch the GSAT-19 into the GTO at 16.20 minutes after lift off.

In 2014, the space agency successfully undertook the first experimental flight of the GSLV MkIII from Sriharikota.

The vehicle in a two-stage flight (with a non-functional cryogenic upper stage) carried the Crew Module Atmospheric Re-Entry Experiment to the intended height of 126 km and re-entered the atmosphere safely.

The GSLV-Mk III-D1 is a three-stage vehicle with indigenous cryogenic upper stage engine designed to carry heavier communication satellites into the GTO.

Apart from the cryogenic engine, designated C25, carrying about 28 tonnes of propellants, it has two solid strap-on motors (S200) and a core liquid booster (L110).

The mission would also augment India’s communication resources as a single GSAT-19 satellite will be equivalent to having a constellation of six to seven of the older variety of communication satellites in space.

At present, out of a constellation of 41 in-orbit Indian satellites, 13 are communication satellites, and the total mission life of the GSAT-19 is 10 years.